The goal of this project is to understand the mechanisms controlling growth and membrane transport and their inhibition by lipophilic acids, which include most anti-microbial food additives, cosmetic preservatives, antiseptics, certain pesticides, and various drugs. Some of the highly lipophilic compounds are known or suspected to cause brain damage or to be teratogens. The reactions of Bacillus subtilis, for which mutants and vesicles of cytoplasmic membranes can be easily obtained, are compared with HeLa and other mammalian cell lines which can be more directly related to the mammalian problem. Results include: (1) The process formation of HeLa cells induced by butyrate and the reversion to a normal cell type were studied. (2) Hexachlorophene inhibits growth by destroying the proton gradient through the cell membrane. Almost all of it is bound to the cells and cannot be removed by washing. However, exposure to bovine serum albumin removes it and restores growth. (3) B. subtilis can grow on aspartate as sole carbon source even when cells lack the (high affinity) aspartate transport system; this growth is sodium dependent.